The present invention relates to cushioning devices for wharfs and docks to which shipping vessels are docked at shipping terminals.
A prior art fender installation on a vertically oriented stationary wharf face includes one or a vertically spaced plurality of resilient support members to which is fastened a plate having resilient tiles thereon. In one configuration, each support member is a conically shaped molding having steel flange reinforcements at opposite ends and having openings therein for receiving threaded fasteners. In another configuration, the support members have generally V-shaped configuration including a pair of diverging vertically oriented flexible web portions diverging from proximate the plate and having respective outwardly projecting flanges that are fastened to the wharf face. Such devices provide resilient lateral support for large ships. However, they exhibit a number of disadvantages. For example:
1. They are expensive to provide in that the resilient tiles require a large number of fasteners for anchoring to the plates;
2. The plates and fasteners are subject to corrosion;
3. The plates are excessively heavy and/or insufficiently strong for resisting expected side loading, particularly at corners of the plates.
Thus there is a need for a composite fender that overcomes the disadvantages of the prior art.
The present invention meets this need by providing a fender panel and assembly that is particularly effective in protecting wharfs from damage by passing or docking ships. In one aspect of the invention, the fender panel includes a resilient body member having a front surface and a rear mounting surface; and a cage frame encapsulated within the body member, the cage frame including an attachment structure connected to plural spaced apart locations of the cage frame, the attachment structure defining a spaced plurality of attachment elements for connecting to supporting structure. The cage frame is spaced from the front face by not less than 10 percent of a panel thickness of the body member between the front face and the rear mounting surface for cushioning the impact of contacting ship hulls. The cage frame preferably includes a grid of rod members for forming a light-weight, high-strength matrix reinforcement of the body member.
The rod members of the cage frame can be steel reinforcing rods having gripping projections formed thereon. Preferably the rod members have a nominal cross-sectional diameter that is not more than 10 percent of the panel thickness for efficient utilization of the steel material. Preferably the grid of the cage-frame has welded connections at respective intersections thereof for enhanced rigidity. The grid can be a front grid, the cage frame further including a rear grid of rod members and a spacer structure connecting portions of the grids in rigidly spaced relation.
The attachment structure can be rigidly connected to the spacer structure, and can include a plate member having respective fastener openings extending through the plate member to form the attachment elements. The plate member can be parallel-spaced from the mounting surface, the attachment structure also including a plurality of tubular spacers extending between the plate member and the mounting surface in alignment with the fastener openings for receiving corresponding threaded fasteners. The spacer structure can be a rectangular frame having pairs of side and end frame members, and the plate member can be welded between the side frame members. The frame members can be formed having a uniform cross-section including spaced pairs of flange portions and connecting web portions, the flange portions forming front and rear faces of the frame.
The grids can include respective pluralities of lateral and longitudinal rods, with some of the lateral rods being connected to the side frame members, and the longitudinal rods being connected to the lateral rods in spaced relation opposite the frame.
The front surface can include a planar main portion and a tapered perimeter portion, a cushion thickness of the resilient body between the main portion of the front surface and the cage frame preferably being at least 30 percent of the panel thickness for enhanced cushioning of impacting vessel hulls. Regardless of the panel thickness the cushion thickness is preferably at least 0.15 meters. Preferably, the resilient body consists of a main polymeric component and an additive component, the main polymeric component being low-density polyethylene of which at least 35 percent is linear low-density polyethylene for preventing cracking and preserving uninterrupted coverage of the cage frame by the resilient body, the additive component including an effective amount of an ultraviolet inhibitor. Preferably the main polymeric component is at least 90 percent of the resilient body, the resilient body including not more than 5 percent by weight of high-density polyethylene. It is also preferable that the main polymeric component be at least 65 percent linear low-density polyethylene.
The cage frame can include a frame having pluralities of first and second beams that are rigidly connected in orthogonal relation, and the cage frame can include the grid of first and second rod members wherein the first rod members are connected between the second rod members and a front face of the frame. The first and second beams can be joined in coplanar relation. The at least some of the second beams can be segmented with each segment extending between a pair of the first beams. The beams can each be formed having a uniform cross-section including front and rear flange portions and a connecting web portion, the flange portions forming respective front and rear faces of the frame.
The attachment elements can be formed in respective boss members that are rigidly connected between respective front and rear flanges of one of the beams. The boss members can be threaded for engaging threaded fasteners. Preferably each of the boss members projects rearwardly from the rear flanges of the beams for reinforcing respective threaded fastener. More preferably, the boss members are formed of corrosion resistant steel and extend flush with the rear mounting surface of the body member for enhancing the reinforcement and for preventing corrosion in case of water leakage between the support and the rear mounting surface of the composite fender panel.
Alternatively, the boss members can be spaced from the mounting surface with a passage being formed for the fastener between the boss member and the mounting surface whereby, when the fasteners are tightened against a support that contacts the mounting surface, the body member is compressed about the fasteners between the mounting surface and the bosses for sealing same. Also, or in the alternative, the boss members can be formed with passages therethrough for receiving threaded fasteners, a cavity being formed between the boss and the front surface of the resilient body for receiving a head of the fastener and a plug for encapsulating the head of the fastener.
The frame can include front and a rear portions that are connected in parallel-spaced relation by a plurality of third beams for imparting added strength to the cage frame.
A composite fender assembly can be formed from the composite fender panel and a resilient support member for mounting the fender panel in resiliently spaced relation to a wharf face, the support member having a plurality of threaded fastener cavities formed in a support surface thereof, the fender panel being attached by a plurality of threaded fasteners that connect respective fastener elements of the fender panel to the support member for rigidly holding the mounting surface of fender panel against the support surface of the support member. The resilient body can be initially formed with head cavities extending between respective fastener openings and the front face, the head cavities being tapered continuously inwardly between the front face and the fastener elements, a resilient plug member being subsequently sealingly bonded within the cavity and forming a portion of the front face. The plug member can adhesively bonded or thermally fused within the cavity.
In another variation, the fastener elements can be formed as threaded openings in the attachment structure for engaging corresponding ones of the threaded fasteners when there is access to heads of the fasteners opposite a flange of the support member.
In another aspect of the invention, a method for forming a composite fender panel includes:
(a) forming a cage frame including a spaced plurality of attachments; and
(b) encapsulating the cage frame in a resilient material forming a resilient body having a front surface and a rear mounting surface, the resilient material being formed for accessing the attachment elements.
The method can further include providing an openable mold assembly having front and rear mold elements for respectively defining the front surface and the rear mounting surface, and supporting the cage frame within the mold assembly by a plurality of threaded fasteners engaging respective ones of the fastener openings. The fastener openings can be threaded, the fasteners threadingly engaging the fastener openings during the encapsulating.
The cage frame can include the grid of reinforcing rods on a front face of the frame, with first rods being connected to the front face and second rods connected to front edges of the first rods. The cage frame can include the frame having intersecting beam members, and the attachment elements can have respective fastener openings.
The method can further include, prior to the encapsulating, assembling respective spacer sleeves against the frame in registration with corresponding ones of the fastener openings, the spacer sleeves being encapsulated flush with the mounting surface in the encapsulating of the cage frame. Also or alternatively, the encapsulating includes forming respective passages extending from the mounting surface to the fastener openings. Also, the encapsulating can include forming respective head cavities in the body between the front surface and the fastener openings for accessing the fastener openings.
The invention also provides a method for making a composite protective fender assembly, including forming the composite fender panel; providing a resilient support member having a plurality of threaded fastener cavities formed in a supporting surface thereof; fastening the fender panel against the supporting surface using headed fasteners extending from respective head cavities, through the mounting plate, and into engagement with corresponding ones of the threaded cavities; and sealingly filling the head cavities using respective resilient plug members.